In a well-known administration method, a medicinal ingredient or an active ingredient is administered in the form of a tablet containing the ingredient. Particularly in the pharmaceutical field, various tablet-form pharmaceutical products have been widely used for treating or preventing a disease.
Also in several fields other than the pharmaceutical field, e.g. in the fields of FOSHU (Food for Specified Health Uses) and nutritional supplement, tablet-form products have been proposed in recent years. However, in general, a dose adequate to achieve a desired effect of an active ingredient in the nutritional supplement or the like is significantly larger than that of a medicinal ingredient in the pharmaceutical product. Therefore, for example, the user of the nutritional supplement or the like has to take in a larger-sized tablet or a larger number of tablets in a single dose, and thus bears a large intake burden.
The content of the active ingredient in the tablet may be increased to solve the above problem. However, the content of an auxiliary ingredient such as a binder is relatively reduced to cause a problem with poor tabletability, tablet breakage due to insufficient binding strength, or the like.
Use of a casein in a tablet is described e.g. in the following documents.
Patent Document 1 discloses a casein for use as a surface stabilizer in a process of tableting a composition containing an active nanoparticle ingredient. Patent Document 2 discloses a tablet confectionery containing a casein phosphopeptide as a bitterness inhibitor. Patent Document 3 discloses a coenzyme Q10 composition containing a casein and a saccharide other than polysaccharides, and further discloses a tablet containing the composition. However, in the documents, the caseins are used as auxiliary ingredients, and the tablets have remarkably low casein concentrations.
Meanwhile, Patent Document 4 discloses that a casein hydrolysate has an angiotensin converting enzyme inhibitory effect or a hypotensive effect, and Patent Document 5 discloses that a casein hydrolysate containing a particular peptide has a brain function improving effect.
Therefore, the casein hydrolysates have attracted much attention also as active ingredients due to the above effects.    Patent Document 1: JP 2013-209422 A    Patent Document 2: JP 2012-217442 A    Patent Document 3: WO 2009-001787 A    Patent Document 4: WO 2005-012542 A    Patent Document 5: JP 2013-5763 A